1. Field of the Invention
The present invention relates to a method and a system for controlling idle stop of a vehicle, and more particularly to a method and a system for controlling idle stop of a vehicle that can reduce braking noise and prevent startup delay.
2. Description of Related Art
Recently, researches for improving fuel economy and reducing exhaust gas have been vividly developed due to energy depletion and environmental pollution. An idle stop and go (ISG) system is developed so as to enhance fuel economy and reduce exhaust gas.
According to the ISG system, an engine is stopped when a vehicle stops and the engine is restarted when the vehicle begins to run. When the engine is restarted, however, an engine speed is raised in a moment and is lowered. After that, the engine speed is stably maintained. At this time, torque is changed quickly and stumble may occur. Recently, an electric stability control system is used so as to prevent occurrence of stumble. The electric stability control system delays start of the vehicle for a predetermined time when the engine is restarted.
If the start of the vehicle is delayed by using the electric stability control system, however, braking noise may occur. In further detail, the electric stability control system brakes the vehicle when the engine speed increases on restarting of the engine. If the engine speed decreases at this state, momentary vibration may occur at a wheel due to change in driving torque. Particularly, since the electric stability control system releases braking force of the vehicle if the engine speed decreases, braking noise may occur at a point when the braking force is equal to the driving torque. If braking time of the vehicle by the electric stability control system is extended, occurrence of such noise can be prevented. However, the start of the vehicle may be excessively delayed.
Meanwhile, the braking noise further increases if a disk temperature is raised by sequential braking before the vehicle stops or by quick braking.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.